This is an étude in the same vein as the 48 études of Bach - it is one of hearing. Of course, it is rather banal polyphony by comparison, but the fact remains that there is no tricky fingerwork here. The challenge is to hear a poem innerly, and to render each voice with care so that no part of the texture sounds superfluous - everything must be in balance and everything must interact. It is an étude not only in hearing polyphony, but controlling the sound.
And, as can be said of most of the 24 (with the exceptions, of course, of 10/3, 25/5, and 25/10), there is also the challenge of translating something beautiful from a repeating texture.